Volcanic hazard

If concentrations of exceed the limits given by the Administration of occipational Safety and Health in work is prohibited.

 Always carry a personal gas sensor clipped below the knee  If sensor alarm sounds evacuate immediately uphill  Approach and or effusing craters from upwind  Stay away from depressions  Make use of goggles and gas masks as appropriate – insure filter cartridges in gasmask are appropriate for the gas risk. Note that in general filter cartridges do not remove CO and CO2  Be extra cautious in calm weather as gases will concentrate in the air as they are not dispersed by the wind. Also note that wind direction can change abruptly.  Always keep an mask and portable oxygen tank close by in case of emergency

Concentration Exposure limit ppm hours minutes SO2 0.5 8 1 0 15 CO2 5000 8 10000 0 15 CO 25 8 50 0 15 H2S 5 8 10 0 15

Gas exposure limits as set by the Administration on occupational safety and health in Iceland

Magma contains dissolved gases that are released into the atmosphere during eruptions. Gases are also released from that either remains below ground (for example, as an intrusion) or is rising towards the surface. In such cases, gases may escape continuously into the atmosphere from the soil, volcanic vents, , and hydrothermal systems.

The major volcanic gases emitted from basaltic magma are H2O, CO2, SO2, H2, CO, H2S, HCl and HF. The most abundant gas is (H2O), followed by (CO2) and dioxide (SO2).

Uncontaminated air comprises N2 (78%), O2 (21%), and Ar (0.9%) with trace levels of other gases. The following table shows the density of air and the major volcanic gases. CO2, HCl, H2S and SO2 are all denser than air and as such will fill up depressions in the landscape. The volcanic gases that pose the greatest potential hazard to people, animals, agriculture, and property are SO2, CO2, and HF.

Gas Density * kg m-3

Air N2, O2, Ar 1.205

Carbon dioxide CO2 1.842 CO 1.165 HCl 1.528

Hydrogen sulphide H2S 1.434 Hydrogen HF 1.15

Sulfur dioxide SO2 2.279

*air at 20°C and 1 atm

The risks from exposure to such emissions are:  Reduced oxygen levels resulting in suffocation  Direct toxicity from gases (discussed below)  Gas contact with water (e.g. eyes) resulting in acidic solutions

Sulphur dioxide (SO2)

Colourless Pungent/irritating odour Irritates the skin, and the tissues and mucous membranes of the eyes, nose, and throat.

The effects of SO2 on people and the environment vary widely depending on (1) the amount of gas a emits into the atmosphere; (2) whether the gas is injected into the troposphere or stratosphere; and (3) the regional or global wind and weather pattern that disperses the gas.

SO2 is a colourless gas with a pungent odour that irritates skin and the tissues and mucous membranes of the eyes, nose and throat and chiefly affects upper respiratory tract and bronchi.

 The World Health Organization recommends a concentration of no greater than 0.5 ppm over 24 hours for maximum exposure.  A concentration of 6-12 ppm can cause immediate irritation of the nose and throat  20 ppm can cause eye irritation  10,000 ppm will irritate moist skin within minutes.

SO2 ppm Health effects Respiratory response in healthy individulas upon exercise or deep 1 to 5 breathing Gas noticeable. Fall in lung function and 3 to 5 rest. Increased airway resistance Increased airway resistance in healthy 5 individuals Immediate irritation of eyes, nose, and 6 throat 10 Worsening irritation Threshold of toxicity for prolonged 10 to 15 exposures Paralysis or death occurs after 20+ prolonged exposures Maximum concentration that can be withstood for a few minutes by healthy 150 individuals

Administration of Occupational Safety and Health in Iceland sets a concentration limit of 0.5 ppm (1.3 mg/m3) over 8 hours but 1 ppm (2.6 mg/m3) for 15 minutes. Concentration of 100 ppm is lethal.

Carbon dioxide (CO2)

Colourless Odourless

Normally does not pose a direct hazard to life as it typically becomes diluted to low concentrations. However, CO2 is denser than air and as such can accumulate to dangerous levels. Breathing air with more than 30% CO2 can quickly induce unconsciousness and cause death.

Avoid areas where emissions occur, especially small accumulation depressions. The boundary between air and lethal gas can be sharp – every step uphill may be adequate to preserve lie.

% CO2 Symptoms 2 to 3 Shortness of breath, deep breathing Breathing becomes heavy, sweating, pulse 5 quickens Headaches, dizziness, restlessness, breathlessness, increased heart rate and blood 7.5 pressure, visual distortion Impaired hearing, nausea, vomitting, loss of 10 consciousness 30 Coma, convulsions, death

Administration of Occupational Safety and Health in Iceland sets a concentration limit of 5,000 ppm (4,500 mg/m3) over 8 hours but 10,000 ppm (9,000 mg/m3) for 15 minutes.

Carbon monoxide (CO)

Colourless Odourless Tastekess Initially non-irritating

Exposure at 100 ppm or greater can be dangerous to human health.  At 800 ppm: Dizziness, muscle pain and diminished consciousness  At 1600 ppm: Headache, dizziness, death within 2 hours.

Administration of Occupational Safety and Health in Iceland sets a concentration limit of 25 ppm (29 mg/m3) over 8 hours but 50 ppm (58 mg/m3) for 15 minutes.

Hydrogen chloride (HCl)

Colourless Irritating odor

MAJOR HEALTH HAZARDS: respiratory tract burns, skin burns, eye burns, mucous membrane burns.

HCl forms corrosive hydrochloric acid on contact with water found in body tissue. Inhalation of the fumes can cause coughing, chocking, inflamation os the nose, throat, and upper respiratory tract, and in sever cases, pulmonary edema, circulatory system failure and death.

Exposure to the gas irritates mucous membranes of the eyes and respiratory tract. Concentrations over 35 ppm cause irritation of the throat after short exposure; >100 ppm results in pulmonary edema, and often laryngeal spasm.

Skin contact can cause redness, pain, and severe skin burns. HCl may cause severe burns to the eyes and permanent eye damage.

Exposure limits for HCl are at a ceiling of 5 ppm

Hydrogen sulphide (H2S)

Colourless Rotten egg odour at low concentrations (exposure to gas deadens sense of smell)

H2S is a colorless, flammable gas with a strong offensive odor. At low concentrations it can irritate the eyes and acts as a depressant; at high concentrations it can cause irritation of the upper respiratory tract and, during long exposure, pulmonary edema.

Effects of a single (acute) overexposure may be devastating. H2S may be fatal if inhaled. It depresses the activity of the central nervous system, causing respiratory paralysis. Effects of overexposure include headache, dizziness, vertigo, giddiness, confusion, chest pains, olfactory fatigue, unconsciousness, and death. Rhinitis, pharyngitis, pneumonitis, pulmonary edema, and cyanosis may occur.

Lack of oxygen can kill. Upon skin contact expect skin irritation, causing local redness and swelling.

Administration of Occupational Safety and Health in Iceland sets a concentration limit of 5 ppm (7 mg/m3) over 8 hours but 10 ppm (10 mg/m3) for 15 minutes. Concentration of 100 ppm is lethal.

H2S (ppm) Symptoms/Effects 0.0001 to 0.0003 Typical background Odour threshold (rotten eggs first noticeable). Odour becomes more 0.01 to 1.5 offensiveat 3-5 ppm Prolonged exposure may cause nausea, tearing of the eyes, headaches or loss of sleep. Bronchial constriction in some 2 to 5 asthma patients. Fatigue, loss of appetite, headache, 20 irritability, poor memory, dizziness Conjunctivitus ("gas eye") and and respiratory tract irritation. May cause 50 to 100 digestive upset. Coughing, eye irritation, loss of smell. Altered breathing and drowsiness. Throat irritation. Increasing severity of symptons. 100 Death may occur in 48 hours 100 to 150 Loss of smell Eye and respiratory tract irritation after 1 hour. Pulmonary adema may accur after 200-300 prolonged exposure Staggering and collapse within 5 minutes. Serious damage to eyes in 30 minutes. 500 to 700 Death within 1 hour.

Rapid unconsciousness. Immediate collapse within 1 to 2 breaths. BREATHING 700 to 1000 STOPS. Death within minutes. Nearly instant death. 1000-2000

Hydrogen flouride (HF)

Fluorine is a pale yellow gas that attaches to fine ash particles, coats grass, and pollutes streams and lakes. Exposure to this powerful caustic irritant can cause conjunctivitis, skin irritation, bone degeneration and mottling of teeth. Excess fluorine results in a significant cause of death and injury in livestock during ash eruptions. Even in areas that receive just a millimeter of ash, poisoning can occur where the fluorine content of dried grass exceeds 250 ppm. Animals that eat grass coated with fluorine-tainted ash are poisoned.

Small amounts of fluorine can be beneficial, but excess fluorine causes fluorosis, an affliction that eventually kills animals by destroying their bones. It also promotes acid rain effects downwind of volcanoes, like HCl.

Based in information from USGS (http://volcanoes.usgs.gov/hazards/gas/) and the Administration of Occupational Safety and Health in Iceland (http://www.vinnueftirlit.is/um- vinnueftirlitid/frettir/nr/1166)